Latent heat thermal energy storage system using phase change materials was widely used in solar thermal systems. Here, a novel form-stable phase change composite was successfully prepared. The sebacic acid is encapsulated by carbon nanotube sponge. The as-prepared composite is determined by SEM, FT-IR and XRD and the results show that the paraffin is mostly encapsulated in the pores of carbon nanotube sponge. The DSC measurements indicate that the melting temperature and latent heat of the composite are 121.1 degrees C and 131.8 J g(-1), respectively. The phase change composite could maintain its phase transition perfectly after 200 melting - freezing cycles, and no leakage of sebacic acid was observed by further SEM observation. The as prepared composite shows 27-fold thermal conductivity enhancement as compared to the pure sebacic acid. Further, the as-prepared composite shows great photo-thermal performance when under simulated solar irradiation. Hence, the carbon nanotube sponge based high temperature phase change composite has great potential in solar thermal application.